The effect of short-term treatment with lithium carbonate on the outcome of radioiodine therapy in patients with long-lasting Graves' hyperthyroidism

Concomitant lithium increases radioiodine uptake and absorbed doses per administered activity in graves' disease: comparison of conventional versus lithium-augmented radioiodine therapy

Background

Lithium inhibits iodine and thyroid hormone release from thyroid cells, possibly increasing radioiodine retention and anti-hyperthyroid efficacy when given adjunctively to radioiodine therapy (RAI) of Graves’ disease (GD). However, the literature contains limited dosimetric data regarding the influence of concomitant lithium in this setting.

Methods

We retrospectively compared dosimetric variables in patients undergoing RAI with/without adjunctive lithium (n = 52 each). We assessed two low-dose, short-duration oral lithium carbonate regimens, 450 mg/d (n = 22) or 900 mg/d (n = 30), for a mean of 4.7 ± 1.4 d starting upon RAI administration. Patients underwent diagnostic testing to measure thyroidal radioiodine uptake (RAIU) 24 h ± 2 h after ingesting up to 5 MBq radioiodine, receiving individualized RAI activities 24 h later. Using ≥3 RAIU daily measurements starting 24 h post-RAI, researchers were able to determine the effective radioiodine half-life and absorbed dose to the thyroid; we also calculated the absorbed dose per administered activity concentration within that organ. Rates of GD cure, defined as reaching euthyroidism or hypothyroidism post-RAI, were evaluated in patients with ~6 months or longer post-RAI follow-up.

Results

The lithium dosage subgroups had similar dosimetric values and thus are considered together. Lithium patients and controls had similar average “diagnostic” RAIU (51.1% ± 15.7% vs. 50.6% ± 13.8%, p = 0.820), but the former had significantly higher RAIU post-RAI (56.3% ± 13.5% vs. 49.1% ± 13.5%, p = 0.002), reflecting significantly greater change in the former (+16.2% ± 30.4% vs. -1.8% ± 16.1%, p = 0.001). Radioiodine effective half-life was non-significantly longer in lithium patients (5.43 ± 1.50 d vs. 5.08 ± 1.16 d, p = 0.192). The mean RAI administered activity was 27% less in lithium patients (677 ± 294 MBq vs. 930 ± 433 MBq, p = 0.001), but GD cure rates were similar (83% [39/47] vs. 82% [33/40], p = 0.954), possibly due to the significantly higher thyroid dose in the lithium patients, especially in thyroid gland with a volume ≤ 20 mL (1.04 ± 0.44 Gy/MBq vs. 0.76 ± 0.30 Gy/MBq, p = 0.020). Day 3 serum lithium concentrations were low (450 mg/d: 0.26 ± 0.12 mmol/L, 900 mg/d: 0.50 ± 0.18 mmol/L); no lithium toxicity was noted.

Conclusion

Lithium augmentation may increase the RAIU and thyroid absorbed dose, permitting potentially decreased RAI activities without sacrificing efficacy. Our observations should be confirmed in a prospective, randomized trial.

The EANM guideline on radioiodine therapy of benign thyroid disease

This document provides the new EANM guideline on radioiodine therapy of benign thyroid disease. Its aim is to guide nuclear medicine physicians, endocrinologists, and practitioners in the selection of patients for radioiodine therapy. Its recommendations on patients' preparation, empiric and dosimetric therapeutic approaches, applied radioiodine activity, radiation protection requirements, and patients follow-up after administration of radioiodine therapy are extensively discussed.

Effect of Lugol's solution on 131I therapy efficacy in Graves' disease

PURPOSE

Lugol's solution could control thyroid function and suppress ¹³¹I uptake in hyperthyroidism. This study aimed to investigate the appropriate time to withdraw Lugol's solution before ¹³¹I therapy (RIT) in Graves' disease (GD) patients, and how this should influence ¹³¹I uptake and RIT outcome.

METHODS

Two groups (125 cases and 1805 cases) of GD patients received RIT, who were pre-treated with and without Lugol's solution (RI-CI group and RI group). The RI-CI group was further divided into the following sub-groups depending on the duration span between Lugol's solution withdrawal and RIT: sub-group A, 4-7 d (n = 49); sub-group B, 8-14 d (n = 41); and sub-group C, 15-30 d (n = 35). The highest radioactive iodine uptake rate (RAIU_max), effective half-life (T_eff), TRAb, and free triiodothyronine (FT₃) and free thyroxine (FT₄) levels were compared, and therapeutic outcome was evaluated.

RESULTS

There were no significant differences in RAIU_max, TRAb, and T_eff among the four sub-groups (P > 0.05). Both FT₃ and FT₄ levels in sub-groups A and B were lower than those in group RI and sub-group C (P < 0.05). The outcome of non-hyperthyroidism (euthyroidism + hypothyroidism) in groups RI-CI and RI was significantly different at post-RIT month 1 and 3 (P < 0.05). However, intergroup differences at 6 and 12 months were not significant (P > 0.05).

CONCLUSIONS

Withdrawal of Lugol's solution 4-7 or 8-14 d before RIT does not influence ¹³¹I uptake and RIT efficacy in GD. Moreover, in order to avoid a rapid increase in thyroid hormone levels at the same time, Lugol's solution should be withdrawn 4-7 d before RIT.

Meta-Analysis of Randomized Controlled Trials Comparing the Efficacy of Radioactive Iodine Monotherapy versus Radioactive Iodine Therapy and Adjunctive Lithium for the Treatment of Hyperthyroidism

Background: The objective of this article is to evaluate the outcomes in patients undergoing radioactive iodine (RAI) with adjunctive lithium (Li) therapy versus (vs.) RAI therapy alone for the treatment of hyperthyroidism.Methods: A systematic review of the literature was undertaken to analyze clinical trials comparing RAI with adjunctive Li therapy vs. RAI therapy alone for the treatment of hyperthyroidism.Results: Six randomized-controlled trials (RCT) involving 755 patients were analyzed. RAI with adjunctive Li was associated with a significantly higher cure rate for hyperthyroidism when compared to RAI alone. Furthermore, a significantly higher cure rate for hyperthyroidism at 12 months was achieved with RAI and adjunctive Li. Adjuvant Li with RAI for ≤ 7 days showed significantly higher cure rate compared to RAI alone, whereas > 7 days of adjuvant Li with RAI did not show any difference in cure rate compared to RAI alone. RAI with adjunctive Li was associated with a significantly higher cure rate for patients with Graves' disease compared to RAI alone. There was no significant difference between RAI with adjunctive Li and RAI alone for toxic nodular thyroid disorder (toxic nodule and toxic multinodular goiter) and thyroid volume >40 grams and ≤40 grams.Conclusions: RAI with adjunctive Li therapy demonstrated superiority over RAI therapy alone with regards to both curing hyperthyroidism and, reduced time till cure, with a limited side effect profile. A large multicenter RCT is required, and if this confirms the data from these smaller trials, then this could change current practice.

Lithium carbonate as add-on therapy to radioiodine in the treatment on hyperthyroidism: a systematic review and meta-analysis

BACKGROUND

The main purpose is to investigate the effect of LiCO3 as an add-on therapy with radioactive iodine in increasing the cure and decreasing the T4 level compared to radioactive iodine alone. The primary outcome is the cure rate as defined by the number of hyperthyroid patients who became euthyroid or hypothyroid. The secondary outcome is the T4 level.

METHODS

Four databases were searched (PubMed, Scopus, Web of Science, and Cochrane central library). The inclusion criteria were randomized and non-randomized clinical trials of hyperthyroidism patients receiving LiCO3 with radioiodine compared with hyperthyroidism patients receiving radioactive iodine alone. Included studies were appraised with the risk of bias version 2 tool, according to the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0.

RESULTS

Nine studies were eligible for inclusion in the study, six randomized control trials and three non-randomized control trials. There were 477 patients in the intervention group and 451 patients in the control group. The cure rate was not significantly different between the two groups, while it was significantly increased with 5000 to 6500 mg optimized cumulative dose of LiCO3 compared with the control group, P = 0.0001. The T4 level showed no significant difference between the two groups, P = 0.13.

CONCLUSIONS

LiCO3 adjunct to radioactive iodine did not show significant differences compared with radioactive iodine alone in terms of cure rate or decreasing T4 level. However, the dose of 5000 to 6000 mg of LiCO3 may increase the cure rate.

Is There Any Need for Adjusting 131I Activity for the Treatment of High Turnover Graves' Disease Compared to Normal Turnover Patients? Results from a Retrospective Cohort Study Validated by Propensity Score Analysis

Purpose

To compare ¹³¹I-therapy outcomes in high turnover and normal turnover Graves' disease patients and predict optimal first ¹³¹I activity for high turnover patients.

Methods

Retrospective cohort design (1:2) validated by propensity score analysis. Cohort 1, high turnover (2-h RAIU/24-h RAIU ≥ 1), n = 104, and cohort 2, normal turnover (ratio < 1), n = 208, patients were compared for post ¹³¹I outcome. The cure was defined as a combined euthyroid and stable hypothyroid state following ¹³¹I treatment. Logistic regression analysis was used for identifying prognostic factors. The propensity score was applied; 77 matched pairs (1:1 ratio) of high and normal turnover patients were selected as a validation set.

Results

First ¹³¹I cure rates of 28% in high turnover and 66% in normal turnover groups (p = 0.001) were noted. The therapy cycles (median, 2 vs. 1) and cumulative ¹³¹I activity (median, 15 vs. 7 mCi) were required to cure hyperthyroidism in cohort 1 and cohort 2, respectively. Age (> 44 years), higher grade of goitre, and 2-h RAIU (> 37%) were associated with ¹³¹I therapy failure. The high turnover patients needed a factor of 1.5-2 times more ¹³¹I activity to achieve a similar cure rate compared to the normal turnover patients. The first-dose cure rate was 31% vs. 60% by propensity score analysis (n = 154), no way different (28% vs.66%) from the whole group of 312 patients.

Conclusion

High turnover Graves' disease patients, if administered standard ¹³¹I activity, the outcomes shall be poor. To improve the success rate, ¹³¹I activity should be increased by 1.5 to 2 times in the high turnover patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-020-00674-3.

Update on pediatric hyperthyroidism

PURPOSE OF REVIEW

This review is intended to highlight recent studies which provide new data on the epidemiology and management of children with hyperthyroidism, including neonates.

RECENT FINDINGS

A French study demonstrates differences in age-related trends in incidence of hyperthyroidism in males versus females and suggests the overall incidence may be increasing. New studies confirm the effectiveness and safety of long-term medical therapy (up to 10 years), including from the first randomized trial of short-term versus long-term therapy. Radioiodine ablation (RAI) is the main alternative therapy, though surgery may have some advantages if done in a high-volume center; using higher weight-based doses of I-131 (250 μCI/g thyroid tissue) could increase proportion of patients achieving hypothyroidism and decrease repeat ablations. Maternal or neonatal thyroid-stimulating hormone (TSH) receptor antibodies in children of mothers with Graves' disease, and TSH at 3-7 days of age are good predictors of which neonates will have problems.

SUMMARY

More research is needed on the epidemiology of Graves' disease. Long-term medical therapy well past two years should be considered an option in compliant patients to decrease the number who need definitive therapy. For those receiving RAI, a dose of about 250 μCI/g thyroid tissue should result in fewer cases of persistent hyperthyroidism than lower doses.

Finding the best effective way of treatment for rapid I-131 turnover Graves' disease patients: A randomized clinical trial

BACKGROUND

Rapid I-131 turnover Graves' disease patients have low cure rate. We aimed to compare cure percentage at 12 months among 3 treatment doses of I-131 with or without lithium carbonate (LiCO3) in rapid turnover Graves' disease patients.

METHODS

Sixty Graves' disease patients referred for radioactive iodine treatment were randomised into three arms of treatment: Group A, 3.7 MBq I-131/g thyroid plus 600 mg/day LiCO3, Group B, 5.55 MBq I-131/g plus 600 mg/day LiCO3, and Group C, 7.4 MBq I-131/g without LiCO3. Data were collected at baseline, 3, 6, 9, and 12 months. The primary endpoint were cure rates (percentage of euthyroid or hypothyroid) at 12 months. Pairwise comparisons were made across 3 groups using an equality of proportions test. The secondary endpoint, the odds of cure over the total follow-up for group B and C versus group A, was analyzed using generalized estimating equation (GEE). Side effects of I-131 and LiCO3 treatment were evaluated at 1 to 2 weeks after treatment.

RESULTS

The cure rate at 12 months was 45% (9/20) for group A, 60% (12/20) for group B and 80% (16/20) for group C. The mean difference in proportion cured at 12 months between group C and group A was 35 (7.0 to 66.8)%; P-value = .02. There was a statistically significant difference between cure rates over all follow-up of group C and A after adjustment for sex (adjusted OR = 3.09; 95%CI = 1.32-7.20; P-value = .009), but no significant difference was found between group B and A or C and B in the primary and/or secondary efficacy endpoints. Side effects from the treatment were found in 12% (7/60); 2 in group A, 4 in group B, and 1 in group C. Four of these were likely due to LiCO3 side effects.

CONCLUSIONS

Treatment of rapid turnover Graves' disease patients with high dose I-131 (7.4 MBq/g) provides significantly higher cure rates at 12 months, and 3 times odds of cure than 3.7 MBq/g I-131 plus LiCO3 with lesser side effects. We thus recommend 7.4 MBq I-131/g for treatment in these patients.